Casey Muratori – The Root of The Root of All Evil – BSC 2026

https://www.youtube.com/watch?v=hpj6r6CjJf8

Casey Muratori’s presentation at the Better Software Conference (BSC) 2026 offers a really fascinating, deep historical dive into one of programming’s most famous and polarized maxims: "Premature optimization is the root of all evil". Instead of just offering his own modern interpretation of the rule, Muratori spends the talk tracing the phrase back to its origins to uncover what it actually meant to the people who coined it, and the very human stories behind it.

Here is a breakdown of the key themes and historical points he covers in the talk:

The 1960s Software Crisis

To truly understand the quote, Muratori takes us back to the late 1960s. Computer hardware was rapidly becoming more powerful, but the practices for writing software were lagging far behind. Programmers were still relying heavily on low-level assembly tricks and global goto statements, making large programs unmanageable. This era became known as the "software crisis".

Against this backdrop, three key figures emerged who desperately wanted to bring order to the chaos:

• Edsger Dijkstra: Known for his famous (and controversially titled) letter "Go To Statement Considered Harmful". Muratori highlights a very human side of Dijkstra, noting that he suffered from a deep depression during this time. He felt isolated in his concerns about software complexity, until a 1968 NATO conference showed him that other brilliant minds were equally terrified of the software crisis.
• Tony Hoare: Who pushed for bringing order to data via "records" (what we now call structs or objects). He came to this realization after a disastrous project where a compiler he was working on ran at a grueling pace of two characters per second due to memory thrashing.
• Ole-Johan Dahl: One of the creators of Simula and an early pioneer of object-oriented programming.

These three eventually collaborated to publish a seminal book called Structured Programming in 1972, which heavily influenced the broader computer science community.

Knuth's 1974 Paper

The core phrase finally appears in Donald Knuth's 1974 paper, "Structured Programming with go-to Statements". The main debate in this massive paper was about whether high-level languages still needed goto statements at all. But tucked away in a section on efficiency was the legendary quote.

Muratori meticulously breaks down the math and the context surrounding Knuth's assertion. Knuth claimed that about 3% of a program's source text accounted for a massive portion of its execution time. Thus, programmers shouldn't waste time optimizing the other 97%—which is where the "premature optimization is the root of all evil" part comes in.

However, Muratori points out a crucial nuance that is almost always lost today: Knuth fiercely advocated for taking that critical 3% very seriously. In fact, Knuth believed that every single compiler should natively provide profiling feedback by default, so programmers would never have to blindly guess where that 3% lived.

The Core Takeaway

Ultimately, Muratori concludes that taking the phrase "premature optimization is the root of all evil" out of its rich historical context turns it into an unhelpful, muddy abstraction. When we understand the severe hardware limitations, the very real anxieties of the software crisis, and the tiny scale of the FORTRAN programs they were analyzing at the time, we can have much more productive and nuanced conversations about software performance today. It's a wonderful reminder that knowing the history of our field is vital to understanding the maxims we still live by.